Method for functional testing of a lateral-acceleration sensor

Abstract

A method for functional testing of a lateral-acceleration sensor in a vehicle equipped with a dynamic stability control system. To simulate dynamic acceleration during driving on a curve, the sensor is checked by gravitational acceleration under static conditions. The method involves positioning the vehicle on a transverse ramp with known angle of inclination and comparing the acceleration force measured by the lateral-acceleration sensor with a preset sensor value determined on the basis of the angle of inclination of the ramp. The comparison is performed on the basis of amplitude and sign, and installation errors can be diagnosed based on an error log.

1. A method for functional testing of a lateral-acceleration sensor in a vehicle equipped with a dynamic stability control system including an electronic dynamic stability controller, comprising the steps of providing a level test surface suitable for accommodating said vehicle to simulate the driving position of said vehicle on a level road surface, measuring a first output of said lateral-acceleration sensor when said vehicle is in driving position on said level test surface to determine the sensor value that is valid for driving in a straight line, said first output having an amplitude and sign, tilting said vehicle such that its entire length is disposed at a preselected angle of inclination transverse to the driving direction to simulate the driving position of said vehicle on a curved road surface, measuring a second output of said lateral-acceleration sensor when said vehicle is in tilted position to determine the sensor value that is valid for driving on a curve, said second output having an amplitude and sign, calculating a preset sensor value simulating dynamically acting centrifugal acceleration by gravitational acceleration statically acting on said lateral-acceleration sensor at said preselected angle of inclination, said preset sensor value having an amplitude and sign, and comparing the amplitude and sign of said second output with the amplitude and sign of said calculated preset sensor value. 
   
   
     2. The method according to  claim 1 , wherein the preset sensor value is calculated based on said preselected angle of inclination. 
   
   
     3. The method according to  claim 1 , further comprising the step of recognizing functional installation of said lateral-acceleration sensor when said output of said sensor changes with a change in position of said vehicle from level to tilted position and said output of said sensor becomes equal in amplitude and sign to said preset sensor value when said vehicle is positioned at said predetermined angle of inclination. 
   
   
     4. The method according to  claim 3 , further comprising the step of displaying said output of said lateral-acceleration sensor via a display device connected to said electronic dynamic stability controller. 
   
   
     5. The method according to  claim 4 , wherein said display device is an on-board display installed in said vehicle. 
   
   
     6. The method according to  claim 3 , further comprising the step of displaying said output of said lateral-acceleration sensor via a diagnostic test instrument connected to said electronic dynamic stability controller. 
   
   
     7. The method according to  claim 1 , wherein said steps of providing a level test surface for said vehicle, measuring a first output of said lateral-acceleration sensor, tilting said vehicle, measuring a second output of said lateral-acceleration sensor, calculating a preset sensor value and comparing said second output and said preset sensor value are effected as an inspection conducted at the end of an assembly line on which said vehicle has been completed. 
   
   
     8. The method according to  claim 1 , wherein said steps of providing a level test surface for said vehicle, measuring a first output of said lateral-acceleration sensor, tilting said vehicle, measuring a second output of said lateral-acceleration sensor, calculating a preset sensor value and comparing said second output and said preset sensor value are effected as part of a general inspection by an authorized inspection agency. 
   
   
     9. The method according to  claim 1 , wherein said step of tilting said vehicle is effected by positioning said vehicle on a transverse ramp having said predetermined angle of inclination. 
   
   
     10. The method according to  claim 9 , further comprising the steps of inputting said measured sensor value valid for driving in a straight line into said electronic dynamic stability controller, applying an offset correction for said input sensor value, inputting said measured sensor value valid for driving on a curve into said electronic dynamic stability controller, utilizing said dynamic stability controller to compare said input sensor value valid for driving on a curve in amplitude and sign with said preset sensor value, and generating a log via said dynamic stability controller. 
   
   
     11. A method for functional testing of a lateral-acceleration sensor in a vehicle equipped with a dynamic stability control system including an electronic dynamic stability controller, comprising the steps of providing a level test surface suitable for accommodating said vehicle to simulate the driving position of said vehicle on a level road surface, measuring a first output of said lateral-acceleration sensor when said vehicle is in driving position on said level test surface to determine the sensor value that is valid for driving in a straight line, said first output having an amplitude and sign, tilting said vehicle such that its entire length is disposed at a preselected angle of inclination transverse to the driving direction to simulate the driving position of said vehicle on a curved road surface, measuring a second output of said lateral-acceleration sensor when said vehicle is in tilted position to determine the sensor value that is valid for driving on a curve, said second output having an amplitude and sign, calculating a preset sensor value corresponding to gravitational acceleration acting on said lateral-acceleration sensor at said preselected angle of inclination, said preset sensor value having an amplitude and sign, comparing the amplitude and sign of said second output with the amplitude and sign of said calculated preset sensor value, recognizing functional installation of said lateral-acceleration sensor when said output of said sensor changes with a change in position of said vehicle from level to tilted position and said output of said sensor becomes equal in amplitude and sign to said preset sensor value when said vehicle is positioned at said predetermined angle of inclination, and generating a log using diagnostic software, said log providing at least one of a confirmation that said lateral-acceleration sensor has been functionally installed and an indication that said lateral-acceleration sensor has not been functionally installed, said indication that said lateral-acceleration sensor has not been functionally installed including information as to the details of errors associated with said sensor. 
   
   
     12. The method according to  claim 11 , wherein said diagnostic software includes an algorithm that is processed by said electronic dynamic stability controller. 
   
   
     13. The method according to  claim 11 , further comprising the step of outputting said log via an on-board display installed in said vehicle. 
   
   
     14. The method according to  claim 11 , further comprising the step of outputting said log via a hard-copy device adapted to be connected to said electronic dynamic stability controller.